A telephone is conventionally "dialed" by a calling party pressing a series of keys on the telephone. Each key suppression is sensed by telephone circuitry, and converted into a corresponding electrical signal, such as a dual tone multi-frequency (DTMF) signal. A public switched telephone network (PSTN), or other central switching system, interprets these DTMF signals, and routes the call appropriately.
As a time saving feature, many telephones incorporate "speed dial" buttons. A typical telephone incorporating this feature has on the order of 10 speed dial buttons. Each speed dial button is programmed by the user to correspond to a particular telephone number. When a programmed speed dial button is pressed by the user, the telephone circuitry creates a series of DTMF signals corresponding to the programmed telephone number, and transmits these DTMF signals to the PSTN. Thus, from the perspective of the PSTN, it appears as if the user pressed the keys corresponding to the programmed telephone number, when the user in fact merely pressed the speed dial button.
As an alternative, some telephones incorporate speed dial functionality without providing separate speed dial buttons for each programmed number. An example of such a telephone is one that has a memory button that works in conjunction with the numeric buttons on the telephone keypad. For example, a user of such a telephone presses "memory" "3" in order to call the telephone number programmed for the third memory location, and the telephone circuitry acts to produce the corresponding DTMF signals.
A drawback of each type of conventional speed dial telephone is that the user must take the time to initially program the speed dial numbers into the speed dial memory. Another drawback is that the user must take additional time to reprogram the speed dial numbers in the speed dial memory when circumstances change. For example, if a user has her mother's telephone number programmed into the memory location corresponding to the first speed dial button, such that pressing the first speed dial button results in an outgoing call to the user's mother, then the user must reprogram this memory location if her mother's telephone number changes, such as when her mother moves or when her mother's area code changes. If the user does not reprogram the memory location, then suppression of her mother's speed dial button will no longer result in a telephone call to her mother.
A drawback related to the time and effort needed to program and reprogram speed dial numbers is that many users effectively elect not to use this feature. Such users either never make the effort to initially program the speed dial memory when first acquiring the telephone, or make an initial programming effort, but never update the programming when circumstances change, thereby leaving the speed dial memory in a perpetual out of date state.